Preheat the oven to 375°F and line a large baking sheet with parchment paper.
Cut your potatoes into quarters if you have large potatoes or into halves if they are small, making sure they are all a similar size so that they cook at the same time.
Toss the potatoes in a large bowl with the olive oil, garlic, Parmesan, salt, and pepper until they are coated all over.
Spread the coated potatoes out over the baking sheet in a single layer, dot with the butter, and place in the oven to roast for 35-40 minutes, or until tender and a little crispy on the outside.
Transfer to a serving dish, sprinkle with the chives, and serve.